Have run into a weird situation. I was trying to boot into a different partition and when I rebooted the machine the partition boot screen that shows up prior to choosing/booting into a partition never showed up.

Fortunately the machine did boot into the default partition so I am able to use that partition.

sda2 is the default partition that is booted into currently. sdb1 is the partition I want to also to be able to boot into.

My original thought was it had something to do with a grub setting or in that area of software I can repair.

Another thing is that the graphics card splash screen no longer momentarily displays during the boot sequence.
I did do an email into the thinkpenguin folks who built the box, asking if they recognize the symptoms. They responded that I shouldn't worry about it atm and that if it doesn't boot at all, just email for a RMA .... it's only our work computer ....

Did do the 'remove the motherboard battery for 10 minutes' and no joy.

You still did not say what is on the partitions you want to boot. I'ts all Linux but which distro is where? Which one was installed first? EFI or BIOS?

Anyway, I can already see a problem: sda is of DOS type and has a BIOS install. sdb is of GPT type and probably has an EFI install but the EFI partition is gone. Mixing this will most likely cause problems. Either have only BIOS installs or only EFI installs. So check whether sdb is really EFI by looking for the file /sys/firmware/efi on sdb. If it's BIOS we'll have to look for another cause of the problem.

You can also execute /usr/bin/bootinfoscript from the SolydXK install and have a look at the output, I don't remember whether it shows EFI/BIOS.

I bought the box from thinkpenguin in September of last year. It came with the current SoldyK version installed on sda2 and I put SolydK on sdb1. sdb2 is strictly storage though I did format in ext4.

The situation is that it ran fine until I wanted to do a backup of sda2 by logging into sdb1 and using luckybackup last week. I had previously gone through this procedure on a weekly basis since I got the box and until now everything went fine ( booted, saw the brief gpu splash screen and then the partitiion boot menu ). So, while there is probably validity to your dos/gpt point, until last week it wasn't an issue.

Which is why I'm currently thinking it's a grub issue. As you saw, I can access sda and sdb, so thankfully it's not a show stopper in terms of being able to do work at this point. Are you aware / do you know what areas of grub deal with the production of the partition boot menu? Is it possible to reinstall grub and if so how?

Thanks for any assistance you might be. I do appreciate that I am in over my head atm and that's how we learn I imagine.

I did not have time to look more closely at the results.txt of bootinfoscript until now. I still can't tell you what's wrong but I noticed several more strange things.
1. Why is there a grub.cfg on sda1? What's on sda1 anyway? This partition has the boot flag.
2. The grub.cfg on sda2 has /etc/grub.d/30_os-prober, which sees the system on sdb2 but I don't think it is loaded.
3. sdb2 also has grub.cfg and also this /etc/grub.d/30_os-prober sees the other system.
4. You should correct sda2/etc/fstab: 4 swap partitions are 3 too many. Remove the doublettes and the wrong one.
5. sdb2/etc/fstab has the same problem sda2 has.

Both systems need to be either efi or bios. So please again check for /sys/firmware/efi on BOTH systems. Mount the second system into /media or /mnt. The filemanager should do that for you.